EMFPath
- 1. Mikaël Barbero OBEO
- 2. public void demo(Library l) { List<Book> books = l.getBooks(); Set<Borrower> allBorrowers = new HashSet<Borrower>(); List<Writer> allWriters = new ArrayList<Writer>(); for (Book book : books) { List<Borrower> borrowers = book.getBorrowers(); allBorrowers.addAll(borrowers); allWriters.add(book.getAuthor()); } Set<Borrower> filteredBorowers = new HashSet<Borrower>(); for (Borrower borrower : allBorrowers) { if (borrower.getLastName().startsWith("B") && borrower.getBorrowed().contains(aSpecificBook)) { filteredBorowers.add(borrower); } } }
- 3. About Guava Java library used internally Superset of Google @ Google for years Collections s s ti on ti on c lle llec Co 5 Co a r03 a r08 gle v0. gle v1 uav uav G oo G oo G G 2007 2008 2009 2010 2011
- 6. About Guava
- 8. About Guava IO Networking
- 9. About Guava IO Networking Concurrency
- 10. About Guava IO Networking Concurrency Primitive types
- 11. About Guava IO Networking Concurrency Primitive types Collections
- 12. About Guava IO Networking Concurrency Primitive types Collections
- 13. in com.google.common.base package public interface Predicate<T> { Predicate<T> to filter boolean apply(T from); out a collection } pu blic interface Function<F, T> { T apply(F from); Function<F, T> to } transform a collection
- 14. in com.google.common.collect package Iterables.filter() Iterators.filter() Collections2.filter() Sets.filter()
- 15. 24 42 13 7 128
- 16. 24 42 13 7 128 public static void demo(Collection<Integer> c) { Predicate<Integer> isEven = new Predicate<Integer>() { @Override public boolean apply(Integer input) { return (input.intValue() % 2 == 0); } }; Collections2.filter(c, isEven); }
- 17. 24 42 13 7 128 public static void demo(Collection<Integer> c) { Predicate<Integer> isEven = new Predicate<Integer>() { @Override public boolean apply(Integer input) { return (input.intValue() % 2 == 0); } }; Collections2.filter(c, isEven); } 24 42 128
- 18. in com.google.common.collect package Iterables.transform() Iterators.transform() Collections2.transform() Lists.transform()
- 19. Apple Orange Banana Kiwi Pear
- 20. Apple Orange Banana Kiwi Pear public void demo(Collection<String> c) { Function<String, String> toUpperCase = new Function<String, String>() { @Override public String apply(String input) { return input.toUpperCase(); } }; Collections2.transform(c, toUpperCase); }
- 21. Apple Orange Banana Kiwi Pear public void demo(Collection<String> c) { Function<String, String> toUpperCase = new Function<String, String>() { @Override public String apply(String input) { return input.toUpperCase(); } }; Collections2.transform(c, toUpperCase); } APPLE ORANGE BANANA KIWI PEAR
- 22. Compose and combine Functions compose forPredicate Predicates and or not compose
- 23. Beware of
- 25. Copy! Lists.newArrayList() Lists.newLinkedList() Sets.newHashSet() Sets.newLinkedHashSet() Sets.newTreeSet() and make it immutable... ImmutableList.copyOf() ImmutableSet.copyOf()
- 26. Path
- 27. { public interface Function<F, T> Set of functions and } T apply(F from); public interface Predicate<T> { predicates for EMF objects } boolean apply(T from); Code generators for your own Ecore models and few other utility classes
- 28. Lazy EObjects containment tree walking ‣ parent (eContainer) ‣ ancestor ‣ ancestorOrSelf ‣ child (eContents) ‣ descendant (eAllContents) ‣ descendantOrSelf ‣ following ‣ followingSibling ‣ preceding ‣ precedingSibling EObject myObject; Collection<EObject> fs = followingSibling.of(myObject);
- 29. Common predicates Having IsKind/IsType IsAncestor/IsChild public static Collection<EObject> demoHaving(Collection<EObject> c) { return Collections2.filter(c, Having.feature(EcorePackage.Literals.ENAMED_ELEMENT__NAME, StringPredicates.firstUpperCase) ); }
- 30. non-EMF functions & predicates Strings length : Function<String, Integer> toL1Case : Function<String, String> Comparable toLowerCase : Function<String, String> toU1Case : Function<String, String> Predicates to toUpperCase : Function<String, String> test ordering: trim : Function<String, String> equal replaceAll(Pattern, String) less than replaceAll(String, String) greater than replaceFirst(Pattern, String) less or equal replaceFirst(String, String) greater or equal substring(int) substring(int, int)
- 31. Ecore API has been Guava-ified ‣ EObject.eResource() is wrapped as a Function in EObjectPath.eResource ‣ EObject.eIsProxy() is wrapped as a Predicate in EObjectPath.eIsProxy ‣ EClass.getESuperTypes() is wrapped as a Function in EClass.eSuperTypes ‣ EReference.isContainment() is wrapped as a Predicate in ERefrencePath.isContainment
- 32. Ecore has been Guava-ified through a generator + that is available for your own Ecore model
- 33. time to play
- 34. public void demo(Library l) { List<Book> books = l.getBooks(); Set<Borrower> allBorrowers = new HashSet<Borrower>(); List<Writer> allWriters = new ArrayList<Writer>(); for (Book book : books) { List<Borrower> borrowers = book.getBorrowers(); allBorrowers.addAll(borrowers); allWriters.add(book.getAuthor()); } Set<Borrower> filteredBorowers = new HashSet<Borrower>(); for (Borrower borrower : allBorrowers) { if (borrower.getLastName().startsWith("B") && borrower.getBorrowed().contains(aSpecificBook)) { filteredBorowers.add(borrower); } } }
- 35. public void demo2(Library l) { List<Book> books = l.getBooks(); Set<Borrower> allBorrowers = ImmutableSet.copyOf( Iterables.concat( Collections2.transform(books, BookPath.borrowers))); List<Writer> allWriters = Lists.transform(books, BookPath.author); Predicate<Borrower> predicate = new Predicate<Borrower>() { @Override public boolean apply(Borrower borrower) { return borrower.getLastName().startsWith("B") && borrower.getBorrowed().contains(aSpecificBook); } }; Set<Borrower> filteredBorrowers = Sets.filter(allBorrowers, predicate); }
- 36. public void demo2(Library l) { List<Book> books = l.getBooks(); Set<Borrower> allBorrowers = ImmutableSet.copyOf( Iterables.concat( Collections2.transform(books, BookPath.borrowers))); List<Writer> allWriters = Lists.transform(books, BookPath.author); Predicate<Borrower> predicate = new Predicate<Borrower>() { @Override public boolean apply(Borrower borrower) { return borrower.getLastName().startsWith("B") && borrower.getBorrowed().contains(aSpecificBook); } }; Set<Borrower> filteredBorrowers = Sets.filter(allBorrowers, predicate); }
- 37. public void demo2(Library l) { List<Book> books = l.getBooks(); Set<Borrower> allBorrowers = ImmutableSet.copyOf( Iterables.concat( Collections2.transform(books, BookPath.borrowers))); List<Writer> allWriters = Lists.transform(books, BookPath.author); Set<Borrower> filteredBorrowers = Sets.filter(allBorrowers, predicate); }
- 38. Wha t you should remember about this presentation 1. Function and Predicate 2. Lazyness 3. Walking EObjects containment tree along XPath-like axes 4. Code generators for your own Ecore model
- 39. What you should REALLY remember about this presentation 1. Guava is cool! 2. EMF is cool too! 3. EMFPath bridges the gap between Guava and EMF 4. EMFPath is cool - Q.E.D EMFPath v0.4.0 is available NOW! http://code.google.com/a/eclipselabs.org/p/emfpath/
- 40. Q&A